1. Field of the Invention
The present invention relates to an electro-optical composite connector. More specifically, the present invention relates to an electro-optical composite connector comprising a plug connector and a receptacle connector.
2. Description of Related Art
Since optical signals are hardly affected by noises in comparison with electrical signals and can transmit a large amount of data at once, the optical signals can be very useful communication method. Since most of devices use electrical signals, there has been developed an electro-optical composite connector that can be used in such a device while taking advantages of the optical signals. The electro-optical composite connector can freely convert between electrical signals and optical signals.
Such an electro-optical composite connector enables signal transmission between, for example, one device that composes a folding-type cellular mobile phone, i.e., a main body having operation keys, and the other device, i.e., a display having a screen. Furthermore, such an electro-optical connector can directly connect the main body to the display. While sizes of devices become smaller, a connector capable of being mounted on a board without increasing a height dimension has been demanded.
FIGS. 22 and 23 show an example of the electro-optical composite connector. The electro-optical composite connector is disclosed in Japanese Patent Application No. 2005-151264. The conventional connector includes a plug connector 102, which is an optical module, and a receptacle connector 104 as a pair. FIG. 22 is a perspective view of the plug connector 102 and the receptacle connector 104 before fitting to each other. FIG. 23 is a cross-sectional perspective view of the plug connector 102 and the receptacle connector 104 after fitting to each other.
The receptacle connector 104 mainly comprises a receptacle connector housing 161; a receptacle shell 160 that covers the receptacle connector housing 161; and connector terminals 140 disposed and secured in the receptacle connector housing 161. The receptacle connector 104 is mounted on a board.
The receptacle connector housing 161 and the receptacle shell 160 of the receptacle connector 104 form a fitting dent 163 to fit the plug connector 102 therein. The plug connector 102 fits into the fitting dent 163 from an upper side thereof. The receptacle connector 104 has an effective fitting length, which is a necessary height for the fitting. When the plug connector 102 fits into the fitting dent 163 of the receptacle connector 104, the plug connector 102 fits completely in the fitting dent 163. At this time, the connector has a substantially complete rectangular shape as a whole.
The front part 142 of the receptacle connector housing 161 has a terminal securing section, where a plurality of connector terminals 140 is arranged along an extending direction of the sidewall 143. Each connector terminal 140 has a shape of two L-shaped pieces jointed horizontally, and mainly comprises three parts, i.e., a contact section 145, a securing section 146, and a section 148 to dispose on a board 110. While the securing sections 146 are positioned vertically, the sections 148 to dispose on the board 110 are positioned horizontally.
Since a part of a bottom surface of the section 148 to dispose on the board 110 transmits electrical signals to/from the board 110, sections to dispose on the board 110 connect to a wiring (not illustrated) on the board 110. The contact sections 145 are arranged vertically, similarly to the securing sections 146, and can contact with the plug terminals 130 in the plug connector 102 at the terminal contact points 141 when the plug connector 102 fits in the receptacle connector 104.
The plug connector 102 mainly includes a plug connector housing 151; a plug shell 150 to cover an outside of the plug connector housing 151; plug terminals 130 arranged and secured inside the plug connector housing 151; and an optical module board 112. Various components, for example, an optical fiber securing base 115; a securing board 116; an optical transducer 120; a wiring 122; an amplifier 118; and on-board wirings 117(a-e) are mounted on the optical module board 112.
A plurality of plug terminals 130 is arranged in several rows at the front part 156 of the plug connector housing 151 corresponding to positions of the connector terminals 140 of the receptacle connector 104. Each plug terminal 130 has substantially E-shape as a whole, and mainly includes a contact section 135; a securing section 136; a middle extending section 137; and a bottom extending section 138.
The contact section 135 is formed of a vertical base. The securing section 136, the middle extending section 137, and the bottom extending section 138 extend in rows from the contact section 135 horizontally to each other. The securing sections 136 secure the plug terminals 130 in the plug connector housing 151. Especially, the middle extending section 137 and the bottom extending section 138 form a space to press a part of the optical module board 112 therein. When the board 112 is pressed in the plug connector housing 151 from a rear side thereof, a part of the board 112, for example, an edge of the board 112 including the on-board wirings 117 on the board surface, is pressed in the space formed by the middle extending section 137 and the bottom extending section 138. Accordingly, the on-board wiring and the board contact point 131 disposed at the end of the extending section 137 electrically and physically contact to each other.
When the plug connector 102 fits to the receptacle connector 104, the plug terminals 130 of the plug connector 102 and the connector terminals 140 of the receptacle connector 104 electrically contact to each other. With this electrical contact, the connector terminals 140 of the receptacle connector 104 electrically connect to the optical transducer 120 of the plug connector 102. By those connections, photoelectric conversion between the plug connector 102 and the receptacle connector 104 is performed while transmitting electric signals.
The above-described conventional connector is useful as the electro-optical composite connector. However, when the plug shell 150 has a hole or a notch to secure a component, electromagnetic waves leak because of a gap made by the hole or the notch, so that the connector requires an additional member to reduce or prevent electromagnetic interference (EMI). In addition, the above-described conventional configuration is difficult to reduce a height of the connector after mounted on a board. More specifically, in the above-described conventional connector, since the middle extending section 137 and the bottom extending section 138 form the space to press a part of the optical module board 112 therein, the connector requires a certain height enough to form the middle extending section 137 and the bottom extending section 138.
The conventional connector has such a configuration because the connector terminals 130 of the plug connector 102 contact with the contact terminals 140 of the receptacle connector 104 by vertically sliding fitting the plug connector 102 so as to fit in the fitting dent 163 of the receptacle connector 104 from the upper side thereof.
In other words, in this vertical fitting method, since the contact between the connector terminals 130 and the contact terminals 140 may become poor, for example, if the plug connector 102 slightly comes off from the board 110, the connector has to have an enough fitting height to prevent the problem. Therefore, it is difficult to reduce the height of the connector after mounted on a board. Furthermore, according to the above-described configuration, in order to connect the board to ground, it requires a board pattern, which also makes difficult to achieve a low-profile connector.
In view of the problems described above, an object of the invention is to provide an electro-optical composite connector capable of solving the problems of the conventional electro-optical composite connector.
Further objects of the invention will be apparent from the following description of the invention.